1. Field of the Invention
The present invention relates to ductwork assembly apparatuses and, more particularly, is directed to apparatus for assembling L-shaped corner members and elongated flange members into a frame assembly for connecting the adjacent ends of sheet metal ducts.
2. Description of the Invention Background
In the heating, ventilation and air conditioning industry, ducts fabricated from various types of sheet metal materials are typically used to transport conditioned air throughout homes, factories, office buildings and other structures. One could surmise that perhaps there are collectively thousands of miles of such ducts in homes and various other structures throughout the world.
Typical heating, ventilation, and air conditioning duct arrangements comprise rectangular shaped elongated sections that are fastened together at their ends to form a single duct assembly. It has been found that such "sectional" duct assembly is more structurally sound than a single non-sectional duct of similar length. In such sectional duct assemblies, the duct sections must be perfectly aligned to prevent the duct assembly from buckling and to enable airtight seals to be established and maintained between each duct section.
Over the years, a variety of different "flange-type" joint assembly arrangements have been developed for connecting the adjacent ends of rectangular or square sheet metal ducts together. For example, U.S. Pat. No. 3,712,650 to Mez, U.S. Pat. No. 4,288,115 to Sullivan, and U.S. Pat. No. 5,054,823 to Arnoldt disclose various flange-type duct connection arrangements for interconnecting the adjacent ends of rectangular duct sections. Such flange-type connection arrangements typically consist of a pair of rectangular frames that are each constructed from four roll-formed flange members that are adapted to be attached to the edges of adjacent duct ends. The flange members typically comprise an L-shaped member that has an upstanding leg-receiving portion and a duct receiving portion extending perpendicularly therefrom. Four L-shaped corner members, each having relatively planar legs that are adapted to be inserted into the upstanding leg-receiving channels of adjacent flanges, are used to interconnect the flanges to form a rectangular shaped frame. The flanges are precut to predetermined lengths such that when assembled together into a rectangular shaped frame, the frame fits on the end of a corresponding duct for attachment thereto.
During the duct assembly process, the attachment frames are first assembled. Thereafter, each frame is inserted onto an end of a corresponding duct such that the end of the duct is forcibly received in the duct receiving portions of the flange members comprising the rectangular frame. After the frame has been inserted onto the corresponding duct end, it is typically secured to the duct by sheet metal screws, rivets, or spot welds.
After the frames have been attached to the adjacent ends of two duct sections, a gasket material is typically positioned between the frames. The frames are then bolted together in confronting relationship by bolts that extend through the L-shaped corner members. The heating, ventilation, and air conditioning industry has found that such flange-type connection arrangement serves to rigidly interconnect the adjacent ends of ducts together while maintaining a substantially airtight seal between the duct sections.
To ensure that the frame remains together after it has been assembled, the legs of the L-shaped corner members are complementarily dimensioned with respect to the leg-receiving channels of the flange members such that a force or friction type fit is created between the leg and the corresponding flange member. Such force fit arrangement, however, makes assembling the frames difficult and time consuming.
In the past, the frames have been manually assembled. Such assembly operation typically involves grasping a flange member in one hand and inserting the end of a corner leg into the leg-receiving channel of the flange member. The opposite end of the flange member is then abutted against a solid surface, usually the floor, and a rubber mallet or other suitable tool is used to drive the L-shaped corner member into the flange channel. A similar corner/flange assembly is then constructed in the same manner. Thereafter, the ends of the free legs of the four corner members are inserted into the side flange members and the corner members are struck with a hammer to cause the free legs to be inserted into the corresponding channels.
The reader will appreciate that the above-described method of connecting the L-shaped corner members to their corresponding flange members is fraught with many disadvantages. In particular, such an unstable method of supporting the flange member and corner assembly while it is being driven together provides an opportunity for the corner member to become dislodged from the flange member during the assembly process which could injure the individual assembling the flange/corner assembly. Also, if the flange member is not adequately supported, it, too, could strike the person constructing the assembly. It will also be appreciated that longer lengths of flange members are much more difficult to support during the assembly process. The reader will further appreciate that such manual assembly operation can damage the flange members and/or corner members as they are being driven together.
Thus, there is a need for apparatus for inserting the legs of L-shaped corner members into the channel of a corresponding flange member in a safe and efficient manner. There is a further need for an assembly apparatus that is capable of assembling corner members and flange members of different sizes and lengths. There is still another need for apparatus for assembling L-shaped corner members and precut flange members into a complete frame assembly for attachment to a correspondingly sized duct.